1. Field of the Invention
The field of the invention is that of cockpit display systems for aircraft. Modern cockpits are provided with visual display systems comprising complex windowing, making it possible to show several display areas on the same screen simultaneously. Each type of display can be shown in several different ways according to the phase of flight and the flight conditions.
2. Description of the Prior Art
One of the most important representations for the crew is that concerning management of the navigation of the aircraft. This window is frequently called “Navigation Display” or “ND”. This window presents a model of the aircraft, around and below which are displayed the terrain data, called the base map, corresponding to the aircraft position, the flight plan or plans for the aircraft, information concerning the aircraft itself or its means of navigation.
This representation can generally be configured into different types of display. There are two main modes of representation, called “Arc” mode and “Rose” mode. In “Arc” mode, the model of the aircraft is situated at the bottom of the screen and the cartographic data are those situated in front of the aircraft. In “Rose” mode model of the aircraft is situated in the centre of the screen and the cartographic data are those situated all around the aircraft. Obviously, both representations are useful. “Rose” mode provides an overall view of the surroundings of the aircraft. “Arc” mode makes it possible to anticipate the future flight path. As a general rule, the switch from an “Arc”-type representation to a “Rose”-type representation is made using a control button or a hardware selector switch arranged in the cockpit.
FIGS. 1, 2, and 3 illustrate this selection. FIG. 1 schematically shows an aircraft instrument panel comprising six visual display units and a control panel arranged above the instrument panel and comprising a plurality of control positions CP. In FIG. 1, the control position CP in bold lines comprises a selection button B for the desired mode. In FIG. 1, the screen ND displaying the “Navigation Display” window is on the left-hand side of the instrument panel. It is also shown in bold lines. FIG. 2 shows an enlarged view of the control position and the screen displaying the “Navigation Display” window. In this figure, the selector switch B is on “ARC” mode and the window shown clearly displays a model M of the aircraft situated at the bottom of the screen and cartographic data situated in front of the aircraft. When the pilot turns the selector switch B to “ROSE” mode, the graphical representation changes. The model M of the aircraft is now situated at the centre of the screen and the cartographic data are those situated all around the aircraft.
This type of selection has several drawbacks. It is necessary to have one selector per representation of the geographical situation of the navigation of the aircraft. Currently there is one representation on each side of the cockpit, and therefore one associated selector switch on each side of the instrument panel. This drawback can be mitigated by replacing the physical buttons with virtual graphic buttons arranged on the display screens and making it possible to select the desired representation mode, by using graphic pointers, for example. These buttons are sometimes included in multiple-choice menus. This solution has the drawback of adding graphic “tools” to the desired cartographic representation, tools which, most of the time, are only useful when the pilot wishes to change graphical representation. Finally, the abrupt switch from one mode to another is not necessarily the most ergonomic for the pilot.